Generally, a robot such as a humanoid robot has arms, each of which has a hand, such as a gripper for gripping an object or a tool for performing work or processing, on its distal end. Heretofore, when the robot falls down or stands up, the hands of the robot come into contact with a surface on which the robot is supported, such as a floor or ground surface, and the hands in contact with the surface support the body of the robot in cooperation with the arms of the robot. In the conventional robot, the hand and arm therefore function as a supplementary support structure.
However, the above-mentioned conventional supplementary support structure must be configured so that the hand has higher strength than functionally required or has a protective component for its sensor in order to avoid impairment of the functioning of the hand for gripping an object or performing work or processing. This support structure has the problem of increasing the weight of the hand and thus imposing an extra load on a driving system for the hand or arm, and also has the problem of reducing the degree of freedom of the shape or functional design of the hand.